This invention relates to compositions, methods and kits for determining a presence and/or an amount of cortisol including analogs and metabolites thereof in a sample suspected of containing the same. The invention also relates to methods of improving signal separation and low end sensitivity, accuracy and precision in methods for determining an amount of cortisol in samples suspected of containing cortisol.
Cortisol, or hydrocortisone, is a steroid hormone, more specifically a glucocorticoid hormone. Cortisol is synthesized enzymatically in the body from cholesterol, produced by the zona fasciculata of the adrenal cortex. Release of cortisol is controlled by the hypothalmus, usually in response to stress and a low level of blood glucocorticoids. The primary functions of cortisol are to increase blood sugar through gluconeogenesis, suppress the immune system, and aid in fat, protein and carbohydrate metabolism. Cortisol can also result in a decrease of bone formation. In blood, cortisol is bound for the most part by endogenous binding substances such as, for example, certain proteins in the blood. These binding substances include, but are not limited to, corticosteroid binding globulin, albumin and testosterone and estradiol binding globulin, for example.
Assessing cortisol levels in biological samples is important since various synthetic forms of cortisol are used to treat a variety of diseases and since cortisol levels in samples from mammals may provide relevant information regarding, by way of illustration and not limitation, hypercortisolism (Cushing's syndrome), hyperadrenocorticism, proteolysis, muscle wasting, chronic subtle percortisolism (potbelly syndrome), and hypocortisolism (Addison's disease), for example. Furthermore, cortisol may be employed therapeutically to prevent release of substances in the body that cause inflammation, for example.
There is a need for reagents and methods for accurate and sensitive determinations of concentrations of cortisol and analogs and metabolites thereof in samples.